As is known in the art, future diesel engines will be required to run a lower feedgas NOx level in order to meet emission requirements. One way in aiding this process would be to introduce Low Pressure Exhaust Gas Recirculation (LPEGR). In order to properly use this LPEGR, a portion of exhaust from downstream of the Diesel Particulate Filter (DPF) is fed back to the compressor of a turbocharger used with the engine. One way to provide such feedback is to use additional exhaust tubing in order to transport the LPEGR from the tailpipe (after the DPF) to the intake (before the turbo charger).
As is also known in the art, many diesel engine vehicles are fitted with a DPF with dual-walled exhaust pipes for maintaining the exhaust temperatures in the exhaust pipes during critical temperature control fluctuations (regenerations of the DPF in cold weather or in rain conditions).